Highly sensitive ammonia sensor using reflection of light at a glass - photonic crystal interface

TL;DR

This paper presents a novel optical ammonia sensor leveraging photonic crystal deformation and light reflection, achieving high sensitivity and rapid response through capillary vapor condensation at a low cost.

Contribution

It introduces a new effect based on asymmetric deformation of photonic crystals for high-sensitivity optical gas sensing, enabling simple, fast, and cost-effective ammonia detection.

Findings

Sensitivity of 1 ppm for ammonia detection

Response time of 120 milliseconds

Low-cost and easy fabrication of the sensor

Abstract

We have discovered and studied the effect of the asymmetric deformation of a photonic crystal in the form of a change in the slope of the crystal planes as it is filled with a gaseous analyte. We have demonstrated that the use of a new effect leading to the displacement of the stop band against the unchanged spectrum of diffracted white light at the (glass-thin opal film) interface can be used as fast, compact, high sensitive and reproducible optical chemical sensor for ammonia. Low cost and simplicity of sensor fabrication, the response of which can be easily observed without resorting to spectral instruments are therefore likely to be attractive. The basis for high sensitivity (1 ppm), fast response (120 ms) is capillary vapor condensation. On the basis of this effect a cheap high-speed and highly sensitive gas sensors has been built.